AnnotationConfigration merged into Configuration : for most users this is nothing to be conerned with (aside from the fact that AnnotationConfiguration is now deprecated). However, for users still using hbm.xml you should be aware that we chose to use the org.hibernate.cfg.EJB3NamingStrategy used in AnnotationConfigration instead of the older org.hibernate.cfg.DefaultNamingStrategy historically used on Configuration. This may cause naming mismatches; one known place where this is an issue is if you rely on the naming strategy to default the name of a association (many-to-many and collections of elements) table. If you find yourself in this situation, you can tell Hibernate to use the the legacy org.hibernate.cfg.DefaultNamingStrategy by calling Configuration#setNamingStrategy and passing it org.hibernate.cfg.DefaultNamingStrategy#INSTANCE

If you are using Hibernate 3.6.0 with Oracle, the global environment variable, hibernate.jdbc.use_streams_for_binary, must be set to true if you are using materialized_clob or materialized_blob properties. In addition, using java.sql.Clob and java.sql.Blob properties with Oracle is currently broken. See HHH-5659 for details (fixed in 3.6.1).

If you are using Hibernate 3.6.0 with PostgreSQL, the global environment variable, hibernate.jdbc.use_streams_for_binary, must be set to false if you are using clob or blob properties. In addition, using materialized_blob and materialized_clob properties with PostgreSQL is currently broken. See HHH-4617 for details (fixed in 3.6.1).